JP2011061840A - Window control and retransmission control method, and transmitting-side apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of communication quality by avoiding activation of RLC reset processing in a transmitting-side apparatus in the case that a MAC sublayer does not perform order correction processing on a received STATUS-PDU. <P>SOLUTION: In a retransmission control method, a transmitting-side apparatus manages an acknowledgement information receiving window. If a sequence number of a packet included in acknowledgement information received from a receiving-side apparatus is a value out of the range of the acknowledgement information receiving window based on the acknowledgement information relating to the sequence number, the transmitting-side apparatus does not perform window control processing and retransmission control processing of the packet. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a window control and retransmission control method in which a transmission side device performs window control processing and packet retransmission control processing based on delivery confirmation information from a reception side device, and a transmission side device.

  In 3GPP, which is an organization that standardizes third generation mobile communication systems, LTE (Long Term Evolution) is used to dramatically improve transmission speed and shorten transmission delay in a radio access network (RAN). ), And the standard specifications for the elemental technologies related to the study are being developed.

  As shown in FIG. 1, a radio access network (E-UTRAN: Evolved Universal Terrestrial RAN) in an LTE mobile communication system includes a mobile station UE (User Equipment), a radio base station eNB (E-UTRAN Node B), and The mobile station UE and the radio base station eNB are configured to perform communication via a radio link (RL: Radio Link).

  Further, each of the mobile station UE and the radio base station eNB is configured to terminate an RLC (Radio Link Control) sublayer, a MAC (Medium Access Control) sublayer, and a physical (PHY: Physical) layer.

  Also, the transmitting side device (mobile station UE or radio base station eNB) performs RLC processing, MAC processing, and PHY processing on the data to be transmitted in order, and then transmits the data as a radio signal in the radio unit. It is configured.

On the other hand, the receiving side device (mobile station UE or radio base station eNB) extracts transmitted data by sequentially performing PHY processing, MAC processing, and RLC processing on the radio signal received by the radio unit. Is configured to do.

  Here, the data to be transmitted includes user data (U-plane data) generated by an application used by the user, RRC (Radio Resource Control) signaling used for control of the mobile communication system, NAS (Non Access Stratum) signaling, etc. Control data (C plane data).

  Further, an RLC retransmission control process is performed between the RLC sublayer of the transmission side apparatus and the RLC sublayer of the reception side apparatus, and between the MAC sublayer of the transmission side apparatus and the MAC sublayer of the reception side apparatus. In the configuration, HARQ (Hybrid Automatic Repeat Request) retransmission control processing (MAC retransmission control processing) is performed.

  Hereinafter, with reference to FIG. 7, window control and retransmission control processing in the RLC sublayer of the transmission side apparatus based on the acknowledgment information from the RLC sublayer of the reception side apparatus will be described.

  As shown in FIG. 7, when the transmission trigger # 1 of STATUS-PDU (acknowledgment information) occurs, first, the RLC sublayer of the receiving side apparatus depends on the reception status of the current RLC-data-PDU, Next, STATUS-PDU (ACK = 10) for notifying the RLC-data-PDU that is expected to be received is transmitted to the MAC sublayer of the receiving side apparatus.

  Here, the RLC sublayer of the receiving-side apparatus is configured to transmit STATUS-PDU (ACK = 10) in a state where the RLC-data-PDU of sequence number # 10 is received without detecting a loss. Has been.

  Secondly, the MAC sublayer of the reception side apparatus transmits STATUS-PDU (ACK = 10) to the MAC sublayer of the transmission side apparatus using HARQ retransmission control processing.

  Third, the RLC sublayer of the transmission side apparatus sets the lower limit value and the upper limit value of the transmission side window to “11” and “11”, respectively, according to the STATUS-PDU (ACK = 10) received from the MAC sublayer of the transmission side apparatus. 522 ". Here, it is assumed that the window size in the transmission side window is “512”.

  In addition, since the lower limit value of the acknowledgment information reception window managed by the RLC sublayer of the transmission side device is equal to the lower limit value of the transmission side window, the RLC sublayer of the transmission side device is received from the MAC sublayer of the transmission side device. In response to the STATUS-PDU (ACK = 10), the lower limit value of the delivery confirmation information reception window is also updated to “11”.

  On the other hand, the upper limit value of the acknowledgment information reception window managed in the RLC sublayer of the transmission side apparatus is set to the value of the youngest sequence number of the packet sent from the RLC sublayer to the MAC sublayer in the transmission side apparatus. Therefore, even if the RLC sublayer of the transmission side apparatus receives STATUS-PDU (ACK = 10), it does not update the upper limit value of the delivery confirmation information reception window.

  Next, when transmission trigger # 2 of STATUS-PDU (ACK = 100) occurs, the mobile communication system operates in the same manner, and the lower limit value and the upper limit value of the transmission side window become “101” and “612”, respectively. Furthermore, the lower limit value of the delivery confirmation information reception window managed by the RLC sublayer of the transmission side apparatus is updated to “101”.

  Here, in the mobile communication system of the IMT-2000 system, as shown in FIG. 8, the RLC-PDU (actually, RLC-PDU) received by the MAC sublayer including the STATUS-PDU (delivery confirmation information) in the transmission side apparatus. -The MAC-PDU to which the PDU is mapped) is subjected to an order correction process, and the STATUS-PDU (delivery confirmation information) is transmitted to the RLC sublayer in the order of the sequence number.

  Accordingly, when the communication state is normal, the sequence number of the packet included in the STATUS-PDU (acknowledgment confirmation information) received by the RLC sublayer of the transmitting device is always the delivery managed by the RLC sublayer of the transmitting device. The value was confirmed to be within the range of the confirmation information reception window.

  Then, tentatively, the sequence number of the packet included in the STATUS-PDU (acknowledgment information) received by the RLC sublayer of the transmission side apparatus is outside the range of the reception confirmation information reception window managed by the RLC sublayer of the transmission side apparatus. When there is a value of, it is determined that the communication state is abnormal, and the RLC sublayer of the transmission side apparatus starts the RLC reset process.

  Here, since the RLC sublayer of the transmission side device does not transmit the RLC-PDU (data packet) until the RLC reset process is completed, the activation of the RLC reset process significantly reduces the communication quality. pay attention to.

RMT specification of IMT-2000: 3GPP TS 25.322 V6.9.0 (2006-09) LTE Stage2 Specification: 3GPP TS 36.300 V8.0.0 (2007-03)

  However, in the LTE mobile communication system, as shown in FIG. 9, the MAC sublayer does not perform the order correction process on the RLC-PDU received including the STATUS-PDU (delivery confirmation information) in the transmission side apparatus. The STATUS-PDU (delivery confirmation information) is transmitted to the RLC sublayer.

  Therefore, in the LTE mobile communication system, as shown in FIG. 10, even when the communication state is normal, the transmission is triggered by the generation of transmission trigger # 1 of STATUS-PDU (delivery confirmation information). STATUS-PDU (ACK = 10) is transmitted when the transmission trigger # 2 of STATUS-PDU (acknowledgment information) is generated by repeating retransmission between MAC sublayers (ACK = 100). It may arrive later than the RLC sublayer of the transmitting device.

  In this case, when processing similar to that of the mobile communication system of the IMT-2000 system is performed, the RLC sublayer of the transmission side apparatus uses the STATUS-PDU (ACK = 100) to receive the lower limit value of the transmission side window (that is, reception of acknowledgment information). If the STATUS-PDU (ACK = 10) generated by the reception status older than the reception status when the STATUS-PDU (ACK = 100) is generated is received after the lower limit of the window is updated to “101” Because the sequence number of the packet included in the STATUS-PDU (ACK = 10) is outside the range of the delivery confirmation information reception window, the RLC reset process is started and the communication quality is significantly deteriorated. There was a problem.

  Therefore, the present invention has been made in view of the above-described problem, and avoids starting up the RLC reset process in the transmission side apparatus when the MAC sublayer does not perform the order correction process on the received STATUS-PDU. Accordingly, an object of the present invention is to provide a window control and retransmission control method and a transmission side apparatus capable of preventing deterioration of communication quality.

  A first feature of the present invention is a window control and retransmission control method in which a transmission side device performs window control processing and packet retransmission control processing based on delivery confirmation information including an acknowledgment response or a retransmission request from a reception side device. The transmission side device manages a delivery confirmation information reception window, and the sequence number of the packet included in the delivery confirmation information received from the reception side device is outside the range of the delivery confirmation information reception window. In the case where the value is, the transmission side device does not perform the window control processing and the packet retransmission control processing based on the delivery confirmation information related to the sequence number.

  In the first aspect of the present invention, the lower limit value of the delivery confirmation information reception window may be the oldest sequence number of a packet that is in the transmission side device and expects a confirmation response from the reception side device. .

  In the first feature of the present invention, the upper limit value of the delivery confirmation information reception window is a value of a packet sent to a lower layer than a predetermined sublayer that performs the window control processing and the retransmission control processing in the transmission side device. It may be the youngest sequence number.

  A second feature of the present invention is a transmission-side device configured to perform window control processing and packet retransmission control processing based on delivery confirmation information including an acknowledgment response or a retransmission request from a reception-side device. The delivery confirmation information reception window is managed, and the sequence number of the packet included in the delivery confirmation information received from the receiving side device is a value outside the range of the delivery confirmation information reception window. In this case, the gist is that the window control process and the packet retransmission control process are not performed based on the delivery confirmation information related to the sequence number.

  In the second aspect of the present invention, the lower limit value of the delivery confirmation information reception window may be the oldest sequence number of a packet that expects a confirmation response from the reception side device in the transmission side device.

  In the second aspect of the present invention, the upper limit value of the delivery confirmation information reception window is a value of a packet sent to a lower layer than a predetermined sublayer that performs the window control processing and the retransmission control processing in the transmission side device. It may be the youngest sequence number.

  As described above, according to the present invention, in the case where the MAC sublayer does not perform the order correction process on the received STATUS PDU, the activation of the RLC reset process in the transmission side device is avoided, thereby preventing the deterioration of the communication quality. A window control and retransmission control method and a transmission-side apparatus can be provided.

It is a figure which shows the protocol layer structure in the radio | wireless access network of the mobile communication system which concerns on the 1st Embodiment of this invention. FIG. 3 is a functional block diagram of an RLC sublayer in the mobile station and the radio base station according to the first embodiment of the present invention. It is a figure for demonstrating the re-division process performed in the RLC sublayer in the mobile station and radio | wireless base station which concerns on the 1st Embodiment of this invention. FIG. 4 is a diagram illustrating an example of a format of STATUS-PDU (ACK) generated by an RLC sublayer in a mobile station and a radio base station according to the first embodiment of the present invention. It is a figure which shows an example of the format of STATUS-PDU (NACK) produced | generated by the RLC sublayer in the mobile station and radio | wireless base station which concerns on the 1st Embodiment of this invention. 5 is a flowchart showing an operation of an RLC sublayer in the mobile station and the radio base station according to the first embodiment of the present invention. It is a sequence diagram which shows operation | movement of the mobile communication system of a LTE system. It is a figure for demonstrating the communication between the MAC sublayer and RLC sublayer in the mobile communication system of an IMT-2000 system. It is a figure for demonstrating communication between the MAC sublayer and RLC sublayer in the mobile communication system of a LTE system. It is a sequence diagram which shows operation | movement of the mobile communication system of a LTE system.

(Configuration of mobile communication system according to the first embodiment of the present invention)
The configuration of the mobile communication system according to the first embodiment of the present invention will be described with reference to FIGS.

  In the present embodiment, as shown in FIG. 1, a mobile communication system having an LTE / SAE (System Architecture Evolution) architecture, which is being standardized by 3GPP, will be described as an example. The present invention is not limited to such a mobile communication system, but can be applied to a mobile communication system having other architecture.

  With reference to FIG. 2, a functional configuration of an RLC sublayer in Acknowledge mode (AM) (hereinafter, RLC sublayer) will be described.

  Note that some or all of the functions (modules) constituting the RLC sublayer shown in FIG. 2 may be realized by hardware or software on the IC chip.

  For example, a function (module) that constitutes a MAC sublayer and a physical layer that are generally simple and require high-speed processing on an IC chip is realized by hardware, and RLC that is generally required to perform complicated processing The functions (modules) constituting the sublayer may be configured to be realized by software.

  Further, the function (module) constituting the physical layer, the function (module) constituting the MAC sublayer, and the function (module) constituting the RLC sublayer may be realized on the same IC chip, or may be different from each other. It may be realized on an IC chip.

  Hereinafter, an example of the configuration of the RLC sublayer in the mobile communication system according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 2, the RLC sublayer includes an RLC-SDU buffer 11, a new transmission buffer 12, a division and integration processing unit 13, an ACK waiting buffer 14, a retransmission buffer 15, an RLC-PDU transmission unit 16, Re-division processing unit 17, RLC-PDU transmission unit 18, RLC-control-PDU generation unit 19, RLC-control-PDU buffer 20, demultiplexing unit 31, order correction buffer 32, and reconstruction buffer 33 And an RLC-SDU reconstructing unit 34.

  The RLC-SDU buffer 11 is configured to store the RLC-SDU received from the upper layer.

  The new transmission buffer 12 is configured to copy and store the RLC-SDU stored in the RLC-SDU buffer 11.

  When the data integration opportunity is notified from the MAC sublayer, the division integration processing unit 13 performs division processing or integration processing on the RLC-SDU (or a part thereof) stored in the new transmission buffer 12, An RLC-data-PDU having a maximum size within the range of the allowable transmission data amount notified from the MAC sublayer is generated.

  The division integration processing unit 13 is configured to transmit the generated RLC-data-PDU to the RLC-PDU transmission unit 16 and store it in the ACK waiting buffer 14.

  The ACK waiting buffer 14 is an RLC-data-PDU from the division integration processing unit 13, an RLC-data-PDU or RLC-data-Sub-PDU from the retransmission waiting buffer 15, or an RLC- It is configured to store a data-Sub-PDU.

  The ACK waiting buffer 14 determines whether or not retransmission is necessary for the stored RLC-data-PDU or RLC-data-Sub-PDU, and determines whether the retransmission is necessary or RLC-data-PDU or The RLC-data-Sub-PDU is configured to be transmitted to the retransmission buffer 15.

  Here, for example, when the ACK waiting buffer 14 receives a STATUS-PDU (NACK) from the RLC sublayer of the receiving side device and a NACK from the MAC sublayer, the stored RLC-data-PDU or RLC- It is determined that it is necessary to retransmit the data-Sub-PDU.

  FIG. 4 shows a format example of STATUS-PDU (ACK) used in the mobile communication system according to the present embodiment.

  As shown in FIG. 4, the STATUS-PDU (ACK) includes a “Type” field, a “Control PDU Type” field, and a “Commutative ACK SN” field.

  The “Type” field is a field indicating the type of RLC-PDU (for example, STATUS-PDU).

  The “Control PDU Type” field is a field indicating the type of RLC-control-PDU (such as STATUS-PDU (ACK) or STATUS-PDU (NACK)).

  The “Commutative ACK SN” field is a field indicating the value of the lower limit value-1 of the receiving side window managed by the RLC sublayer of the receiving side device.

  FIG. 5 shows a format example of STATUS-PDU (NACK) used in the mobile communication system according to the present embodiment.

  As shown in FIG. 5, the STATUS-PDU (NACK) includes a “Type” field, a “Control PDU Type” field, a “Selective NACK SN” field, a “Selective NACK First Octet” field, and a “Selective NACK LACK”. And an “Octet” field.

  Here, the payload portion of the STATUS-PDU (NACK) may include a plurality of “Selective NACK SN” fields, a “Selective NACK First Octet” field, and a “Selective NACK Last Octet” field.

  The “Selective NACK SN” field is a field indicating the sequence number of the RLC-data-PDU that is determined to require RLC retransmission within the reception-side window managed by the RLC sublayer of the reception-side device.

  The “Selective NACK First Octet” field is a field indicating from which byte (octet) retransmission is required in the RLC-data-PDU specified by the “Selective NACK SN” field.

  The “Selective NACK Last Octet” field is a field that indicates how many bytes (octets) need to be retransmitted in the RLC-data-PDU specified by the “Selective NACK SN” field.

  The ACK waiting buffer 14 is configured to manage the transmission side window and the delivery confirmation information reception window.

  Specifically, the ACK waiting buffer 14 receives the transmission side window and the delivery confirmation information defined by the state functions “Window_Size”, “VT (A)”, “VT (S)”, and “VT (MS)”. Manage windows.

  Here, “Window_Size” is a value common to the RLC sublayer of the transmission side device and the RLC sublayer of the reception side device, and does not receive a STATUS-PDU (ACK) from the RLC sublayer of the reception side device. Indicates the maximum number of RLC-PDUs that can be transmitted.

  “VT (A)” is the lower limit value of the transmission side window and the acknowledgment information reception window, that is, RLC-data-PDU (packet) that expects STATUS-PDU (ACK) from the RLC sublayer of the reception side device. Indicates the value of the oldest sequence number.

  “VT (S)” indicates the value of the next sequence number to be added to the RLC-data-PDU (packet) newly transmitted from the RLC sublayer to the MAC sublayer in the transmission side apparatus.

  That is, “VT (S) −1” indicates the value of the youngest sequence number of the RLC-PDU (packet) transmitted from the RLC sublayer to the MAC sublayer in the transmission side apparatus, and the upper limit value of the delivery confirmation information reception window Will be shown.

  “VT (MS)” indicates the upper limit value +1 of the transmission side window, that is, the sum of “VT (A)” and “Window_Size”.

  Basically, the ACK waiting buffer 14 is based on the sequence number of the RLC-data-PDU included in the STATUS-PDU (ACK) received from the RLC sublayer of the reception side apparatus, and the transmission side window and the delivery confirmation information reception window. It is configured to update (state function).

  However, the ACK waiting buffer 14 indicates that the sequence number of the RLC-PDU included in the STATUS-PDU (ACK / NACK) received from the RLC sublayer of the receiving side device is a value within the range of the acknowledgment information reception window (“VT ( A) ”≦ sequence number ≦“ VT (S) −1 ”)), the STATUS-PDU (ACK / NACK) associated with the sequence number is ignored, that is, the STATUS-PDU (ACK associated with the sequence number). / NACK), the window control process and the retransmission control process are not performed.

  That is, the ACK waiting buffer 14 determines that the sequence number of the RLC-data-PDU included in the STATUS-PDU (ACK / NACK) received from the RLC sublayer of the receiving device is outside the range of the delivery confirmation information reception window. In this case, the confirmation response or the retransmission request included in the STATUS-PDU (ACK / NACK) is ignored, the state functions of the transmission side window and the delivery confirmation information reception window are updated, and the corresponding RLC-data- The PDU is not retransmitted.

  When the RLC-data-Sub-PDU is specified by the received STATUS-PDU (ACK / NACK), the ACK waiting buffer 14 stores the RLC-data-PDU to which the RLC-data-Sub-PDU belongs. When it is determined that the sequence number is out of the range of the delivery confirmation information reception window, the confirmation response or the retransmission request included in the STATUS-PDU (ACK / NACK) is ignored, and the transmission side window and the delivery confirmation information are ignored. The reception window state function is not updated, and the corresponding RLC-data-Sub-PDU is not retransmitted.

  The retransmission buffer 15 is configured to store the RLC-data-PDU and RLC-data-Sub-PDU from the ACK waiting buffer 14.

  When the data transmission opportunity is notified from the MAC sublayer, the RLC-PDU transmission unit 16 transmits the RLC-data-PDU transmitted from the division integration processing unit 13 and the RLC-data-PDU stored in the retransmission buffer 15. Are transmitted to the MAC sublayer.

  Here, the RLC-PDU transmission unit 16 assigns an RLC-control-PDU (STATUS-PDU or the like) stored in the RLC-control-PDU buffer 20 to the RLC-data-PDU to be transmitted. May be configured to generate and transmit an RLC-data-PDU-piggybacked-control-PDU.

  Further, when generating the RLC-data-PDU to be transmitted, the RLC-PDU transmission unit 16 assigns a new sequence number (“VT (S)”) to the RLC-data-PDU. It is configured.

  Note that the RLC-PDU transmission unit 16 cannot generate an RLC-data-PDU that gives a sequence number (“VT (MS)” or higher) that is larger than the upper limit value of the transmission-side window.

  The re-division processing unit 17 determines one RLC-data stored in the retransmission buffer 15 according to the communication state of the radio link, specifically, according to the allowable transmission data amount notified from the MAC sublayer. -PDU or RLC-data-Sub-PDU is divided to generate a plurality of RLC-data-Sub-PDUs, that is, RLC-data-PDU stored in retransmission buffer 15 or The RLC-data-Sub-PDU is configured to perform subdivision processing.

  In the example of FIG. 3, the re-division processing unit 17 divides the RLC-data-PDU (SN = X) into three RLC-data-Sub-PDUs #A to #C at the time of the first retransmission. At the time of the second retransmission, the three RLC-data-Sub-PDUs #A to #C are divided into three RLC-data-Sub-PDUs # A1 to # A3, # B1 to # B3, and # C1 to # C3, respectively. is doing.

  The RLC-PDU transmission unit 18 is configured to transmit the RLC-data-Sub-PDU subjected to the re-division processing by the re-division processing unit 17 to the MAC sub-layer when the data transmission opportunity is notified from the MAC sub-layer. Has been.

  Here, the RLC-PDU transmission unit 18 adds an RLC-control-PDU (STATUS-PDU, etc.) stored in the RLC-control-PDU buffer 20 to the RLC-data-Sub-PDU to be transmitted. By doing so, the RLC-data-Sub-PDU-piggybacked-control-PDU may be generated and transmitted.

  The RLC-control-PDU generation unit 19 is configured to generate a STATUS-PDU (ACK / NACK) in response to the notification from the order correction buffer 32.

  The RLC-control-PDU buffer 20 is configured to transfer the RLC-control-PDU generated by the RLC-control-PDU generation unit 19.

  The demultiplexer 31 extracts the STATUS-PDU from the RLC-PDU received from the MAC sublayer, transfers it to the ACK waiting buffer 14, and extracts the RLC-data-PDU and the RLC-data-Sub-PDU. The data is transferred to the order correction buffer 32.

  The order correction buffer 32 is configured to perform order correction processing on the stored RLC-data-PDU (or RLC data-Sub-PDU).

  Specifically, the order correction buffer 32 is configured to store RLC-data-PDU (in-sequence) stored in the order of sequence numbers in the reconstruction buffer 33.

On the other hand, the order correction buffer 32 uses an order correction timer for an RLC-data-PDU (out-of-sequence) that is not stored in the order of sequence numbers.
The C-data-PDU detection process is performed, and when a loss for an unreceived RLC-PDU is detected, the RLC-control-PDU generation unit 19 is notified of the loss.

  When the RLC-data-PDU can be constructed from the stored RLC-data-Sub-PDU, the order correction buffer 32 is configured to construct the RLC-data-PDU.

  If the RLC-SDU reconstructing unit 34 can construct the RLC-SDU from the RLC-data-PDU stored in the reconstruction buffer 33, the RLC-SDU reconstructing unit 34 constructs the RLC-SDU and configures the upper layer in order of the sequence number. Configured to send to.

(Operation of the mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 5, the operation of the transmission side apparatus in the mobile communication system according to the first embodiment of the present invention will be described.

  As shown in FIG. 5, in step S101, the RLC sublayer of the transmission side apparatus receives STATUS-PDU (ACK / NACK) from the RLC sublayer of the reception side apparatus.

  Whether or not the sequence number of the RLC-data-PDU specified by the received STATUS-PDU (ACK / NACK) is a value within the delivery confirmation information reception window in step S102 judge.

  In addition, when the RLC-data-Sub-PDU is specified by the received STATUS-PDU (ACK / NACK), the RLC sublayer of the transmission side apparatus determines that the RLC-data-Sub-PDU to which the RLC-data-Sub-PDU belongs. It is determined whether or not the PDU sequence number is a value within the delivery confirmation information reception window.

  When it is determined that the sequence number of the RLC-data-PDU specified by the received STATUS-PDU (ACK) is a value within the delivery confirmation information reception window, in step S103, the RLC sublayer of the transmission side device If necessary (if the sequence number of the RLC-data-PDU specified by STATUS-PDU (ACK) is the lower limit value of the transmission side window), move the transmission side window and the acknowledgment information reception window, that is, Update the state functions in the sending window and the delivery confirmation information receiving window.

  If it is determined that the sequence number of the RLC-data-PDU specified by the received STATUS-PDU (NACK) is a value within the delivery confirmation information reception window, in step S103, the RLC sublayer of the transmitting apparatus Retransmits the RLC-data-PDU.

  On the other hand, when it is determined that the sequence number of the RLC PDU specified by the received STATUS-PDU (ACK / NACK) is a value within the delivery confirmation information reception window, in step S103, the RLC sublayer of the transmission side device The STATUS PDU (ACK / NACK) is ignored, that is, the window control process and the packet retransmission control process are not performed based on the STATUS-PDU (ACK / NACK).

(Operations and effects of the mobile communication system according to the first embodiment of the present invention)
According to the mobile communication system according to the first embodiment of the present invention, as shown in FIG. 7, STATUS-PDU (ACK = 10) transmitted in response to generation of transmission trigger # 1 of STATUS-PDU is When retransmission between the MAC sublayers is repeated, and arrives at the RLC sublayer of the transmission side device later than the STATUS-PDU (ACK = 100) transmitted when the transmission trigger # 2 of STATUS-PDU is generated By ignoring STATUS PDU (ACK = 10), activation of the RLC reset process in the transmission side apparatus can be avoided, and deterioration in communication quality can be prevented.

  The characteristics of the present embodiment described above may be expressed as follows.

  The first feature of the present embodiment is that window control and retransmission control in which the transmission side apparatus performs window control processing and packet retransmission control processing based on delivery confirmation information including an acknowledgment response or a retransmission request from the reception side apparatus. The transmission side device manages a delivery confirmation information reception window, and a sequence number of a packet included in the delivery confirmation information received from the reception side device is within a range of the delivery confirmation information reception window. When the value is an outside value, the gist is that the transmission side device does not perform the window control processing and the packet retransmission control processing based on the delivery confirmation information related to the sequence number.

  In the first feature of the present embodiment, the lower limit value of the delivery confirmation information reception window may be the oldest sequence number of a packet that expects a confirmation response from the reception side device in the transmission side device. .

  In the first feature of the present embodiment, the upper limit value of the delivery confirmation information reception window is a packet transmitted to a lower layer than a predetermined sublayer that performs the window control processing and the retransmission control processing in the transmission side device. May be the youngest sequence number.

  A second feature of the present embodiment is a transmission-side device configured to perform window control processing and packet retransmission control processing based on delivery confirmation information including an acknowledgment response or a retransmission request from the reception-side device. And is configured to manage a delivery confirmation information reception window, and a sequence number of a packet included in the delivery confirmation information received from the receiving side device is a value outside the range of the delivery confirmation information reception window. In some cases, the window control process and the packet retransmission control process may not be performed based on the delivery confirmation information related to the sequence number.

  In the second feature of the present embodiment, the lower limit value of the delivery confirmation information reception window may be the oldest sequence number of a packet that expects a confirmation response from the reception side device in the transmission side device. .

  In the second feature of the present embodiment, the upper limit value of the delivery confirmation information reception window is a packet transmitted to a lower layer than a predetermined sublayer that performs the window control processing and the retransmission control processing in the transmission side device. May be the youngest sequence number.

  Although the present invention has been described in detail using the above-described embodiment, it is obvious for those skilled in the art that the present invention is not limited to the embodiment described in the present specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 11 ... RLC-SDU buffer 12 ... New transmission buffer 13 ... Division integration processing unit 14 ... ACK waiting buffer 15 ... Retransmission buffer 16, 18 ... RLC-PDU transmission unit 17 ... Re-division processing unit 19 ... RLC-control-PDU generation unit 20 ... RLC-control-PDU buffer 31 ... Demultiplexing unit 32 ... Order correction buffer 33 ... Reconstruction buffer 34 ... RLC-SDU reconstruction unit

Claims (1)

A window control and retransmission control method in which a transmission side apparatus performs window control processing and packet retransmission control processing based on acknowledgment information including a confirmation response or retransmission request from a reception side device,
The transmission side device manages a delivery confirmation information reception window,
When the sequence number of the packet included in the delivery confirmation information received from the reception side device is a value outside the range of the delivery confirmation information reception window, the transmission side device includes the delivery confirmation information related to the sequence number. Based on this, the window control process and the retransmission control process for the packet are not performed.

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